In photography and special studio photography and most particularly studio portrait photography, it is common practice to position the subject in front of a background or screen which has the desired background decor. It is, for example, common to provide a neutral, white, black or grey background for portrait photography in a studio but in many cases, when a more artistic effect is desired, it is necessary to create a more complicated decor as a background.
In the past, the most simple approach to providing background decor has been to use color papers or fabrics, specially painted background surfaces or replaceable backdrops preformed with the desired background decor.
Because the various colors which may be required and the various background patterns which may be desired are numerous, this has necessitated a large stock of backdrops in a studio and has resulted in considerable cost for such backdrops, for the storage space and for the handling of the backdrops, i.e. the removal of a previous backdrop and the introduction of a new backdrop. Furthermore, such handling is not always simple because the backdrops may be large and, especially when they must be self-supporting, are heavy.
Of course, it is possible to paint a backdrop in situ with the desired decor but this restricts sharply the artistic selection which may be desired and requires that changes in the desired ambiance occur over long periods of time because the high cost of repainting the background may even exceed the cost of the other systems described above.
Because of these problems it has been proposed to provide a projector which projects upon a surface located behind the subject to be photographed the desired decor. This spot projector comprises, inter alia, an iris and a mask and is disposed in front of the flash lamp illuminating the surface or the subject to be photographed and permitting, by variation of the opening of the iris or by selection of the mask, the projection of light zones of different patterns and sizes so that, for example, circles, triangles, rectangles, lines or other small shapes can be projected on the surface as a background.
This apparatus has been found to be suitable for limited uses, especially for the patterning of small surfaces but cannot be employed to obtain large projections. The heating of the projector limits the utilities still further and perhaps the greatest limitation is the fact that the iris is capable only of projecting zones of shadow and light so that the decor capabilities are minimal.
Another background projector, referred to in the trade as an "episcope" allows an image or an object to be placed on a plate illuminated by a flash and the image thereof to be focused by an objective and reflected by a semitransparent mirror on the objective lens of the photographic apparatus, namely, the portrait camera. The subject to be photographed is placed in front of a special screen and the camera takes the photograph through the semitransparent mirror, the image reflected by this mirror being juxtaposed with that of the subject by the slant of the screen.
With background projector the background does not appear in the photographic set and thus the background projected is not visible except through the viewfinder of the photographic apparatus and the illumination of the subject can present a problem with respect to the appearance of the background while the background may also prevent effective photography of the subject. In any event, without the camera viewfinder, it is impossible for the photographer to arrange the subject against the background with the best effect.